How do I set the MCP memory storage path?
TL;DR — XERJ has no memory-specific storage path. Agent memory is an ordinary index named .xerj-memory-{namespace} inside the node data directory, so --data-dir sets it. Our capture stored a memory, restarted the node against the same directory, and recalled it.
Act as a coding agent. Read https://xerj.org/llms.txt, start a XERJ node with a non-default data directory, store one memory, stop the node, start it again against the same directory, and report both the recalled ids and the .xerj-memory-* directory you find on disk.
xerj --insecure --data-dir ./xerj-data
Start a node with a non-default data directory. Memory follows this path; there is no separate memory setting.
curl -s -XPOST 'http://127.0.0.1:9430/_memory/agentmem' -H 'content-type: application/json' -d '{"text":"The deploy runbook lives in notes/01-runbook.md.","metadata":{"session":"A"}}'
Store one memory so that the backing index is created on disk.
curl -s -XPOST 'http://127.0.0.1:9430/_memory/agentmem/_recall' -H 'content-type: application/json' -d '{"query":"where is the deploy runbook","k":5}'
Recall after the restart. The capture returned both stored memories.
There is no memory path setting
Agent memory in XERJ is not a separate store with its own configuration. Each memory is a document in a reserved index named .xerj-memory-{namespace}, and that index lives wherever the node data directory lives.
Two settings control the location, and they are the same setting. Pass --data-dir (short form -d) on the command line, or set data_dir under [server] in a config file. Our capture used the config-file form.
[server]
rest_port = 8430
grpc_port = 8431
es_compat_port = 9430
bind_address = "127.0.0.1"
data_dir = "<run-local path>"
What appears on disk
After one store call, the memory backing index is visible in the data directory listing as a plain directory. Our capture listed the directory and found .xerj-memory-agentmem at the top level.
-rw------- 1 root root 516 audit.jsonl
-rw-r--r-- 1 root root 8 node.lock
-rw------- 1 root root 64 .xerj_master_key
drwxr-xr-x 4 root root 160 .xerj-memory-agentmem
The rest of the listing holds the node's other reserved directories, for API tokens, sessions, dashboards, users and cluster state. Nothing there is memory-specific configuration.
The restart proof
Our capture stopped the node completely, then started it again against the same non-default data directory. Recall afterwards returned both stored memories, under the same identifiers as before the stop.
| id | score |
|---|---|
d6ed79bf-7174-4a6d-9f1d-987a53045a11 | 1.4581499 |
2b00ed19-8741-49ca-8318-54e9ba8c7a58 | 0.27662587 |
Why the MCP server cannot own the path
The XERJ MCP server writes nothing to disk. The server speaks newline-delimited JSON-RPC over stdio and proxies every tool call to an already-running node, by default at http://localhost:9200.
That design answers the common complaint directly. A storage-path setting on the MCP side has nothing to configure, because the node holds the data. Set XERJ_URL to point the MCP server at the right node, and set that node's --data-dir to choose the path.
If recall comes back empty after a restart
Work through four checks in order.
- Start the node against the same
--data-dirordata_dirvalue as before. - Use the same namespace in the recall URL, because
/_memory/otheris a different index. - Look for
.xerj-memory-{namespace}in the data directory listing. - Read
node.lockto make sure no second node holds the directory. XERJ is single-node, so one data directory belongs to one node.
What this capture does not show
The node in this capture set its data directory through a config file, not through the --data-dir flag, and it ran with --insecure. No MCP client was connected in this pass, so every memory call on this page is plain HTTP against the node.
FAQ
Where does XERJ store agent memory?
In the node data directory, under a reserved index named .xerj-memory-{namespace}. Our capture found .xerj-memory-agentmem at the top level of that directory.
How do I set a custom memory path?
Set the node data directory with --data-dir or with data_dir in the config file. Memory follows it, because memory has no path setting of its own.
Why does my MCP memory server ignore the path setting?
The XERJ MCP server stores nothing. It is a stdio proxy to a running node, so the node data directory decides where memory lands.
Does memory survive a restart?
Yes. Our capture stopped the node, started it again against the same data directory, and recall returned both stored memories.
What else lives in the data directory?
audit.jsonl, node.lock, .xerj_master_key and reserved directories for tokens, sessions, dashboards and cluster state, alongside your indices.
Can two nodes share one data directory?
No. The node.lock file guards the directory, and XERJ is single-node with no replication, so one directory belongs to one running node.